1. Field of the Invention
The present invention relates to an ink-jet head that ejects ink onto a record medium to thereby conduct a recording.
2. Description of Related Art
An ink-jet head is applicable to a recording apparatus such as printers and facsimile machines, etc. The ink-jet head comprises a plurality of nozzles, pressure chambers that communicate with the respective nozzles, an actuator that selectively applies ejection energy to ink contained in the pressure chambers, and the like. Ink is supplied from an ink supply source such as an ink tank, and then distributed among the respective pressure chambers. Upon driving of the actuator, the ink is ejected from the nozzles that communicate with the pressure chambers. According to one of known techniques, this type of ink-jet head comprises, for the purpose of stable ink supply to the pressure chambers, a reservoir that stores ink having supplied from the ink supply source and supplies the ink directly to the respective pressure chambers (see Japanese Published Unexamined Application No. Hei 6-255101).
In the aforementioned technique, the reservoir is provided with a filter that serves to remove foreign materials from ink, so that ink having no foreign materials can be supplied to the pressure chambers, without causing a clogging of the nozzles. However, since the filter blocks out air bubbles as well as foreign materials contained in the ink, the air bubbles stay on the filter, and growth of the air bubbles may cause a change in passage resistance of ink. When the passage resistance changes, ink ejection performance becomes unstable and therefore good image recordings cannot be performed. When the reservoir, even without any filter formed therein, includes a region where ink flows less smoothly, air bubbles stay within the region to cause unstable ejection performance.